System and method for controlling ultra-capacitor charge and discharge in vehicles with auto start/stop systems

ABSTRACT

A system includes an ultra-capacitor and battery system comprising a battery, a DC-DC converter, and an ultra-capacitor. An auto stop/start module is configured to perform an auto stop event of an engine of a vehicle and an auto start event of the engine of the vehicle based on operating parameters while an ignition is ON. A voltage monitoring module is configured to, in response to a request for an auto start event, selectively discharge the ultra-capacitor during cranking for the auto start event, accumulate a plurality of voltage delta values while the ultra-capacitor discharges during the cranking, and selectively disable the auto stop/start module based on the plurality of voltage delta values.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/192,718, filed on Jul. 15, 2015. The entire disclosures of the applications referenced above are incorporated herein by reference.

FIELD

The present disclosure relates to engine control systems for vehicles, and more particularly systems and methods for controlling an ultra-capacitor in vehicles with auto stop/start systems.

BACKGROUND

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

Internal combustion engines combust an air and fuel mixture within cylinders to drive pistons, which produces drive torque. Air flow into gasoline engines is regulated via a throttle. More specifically, the throttle adjusts throttle area, which increases or decreases air flow into the engine. As the throttle area increases, the air flow into the engine increases. A fuel control system adjusts the rate that fuel is injected to provide a desired air/fuel mixture to the cylinders. Increasing the amount of air and fuel provided to the cylinders increases the torque output of the engine.

A vehicle may include an auto stop/start system that increases the vehicle's fuel efficiency. The auto stop/start system increases fuel efficiency by selectively shutting down the engine and disabling the flow of fuel to the engine while the ignition system of the vehicle is ON. While the engine is shut down, the auto stop/start system automatically starts up the engine when one or more start-up conditions are satisfied.

In some circumstances, battery voltage dips during an auto start event after an auto stop event. While some systems such as an engine controller may be designed to handle the battery voltage dips, other vehicle systems such as a transmission controller or other controllers may not be as robust. When the battery voltage dips during an auto start event, these other controllers may enter into a reset mode of operation and/or cause other drivability issues.

SUMMARY

A system includes an ultra-capacitor and battery system comprising a battery, a DC-DC converter, and an ultra-capacitor. An auto stop/start module is configured to perform an auto stop event of an engine of a vehicle and an auto start event of the engine of the vehicle based on operating parameters while an ignition is ON. A voltage monitoring module is configured to, in response to a request for an auto start event, selectively discharge the ultra-capacitor during cranking for the auto start event, accumulate a plurality of voltage delta values while the ultra-capacitor discharges during the cranking, and selectively disable the auto stop/start module based on the plurality of voltage delta values.

In other features, the plurality of voltage delta values is calculated by generating a difference between battery voltage prior to the cranking and the battery voltage at predetermined time intervals during cranking. The plurality of voltage delta values is calculated by generating a difference between zero and a battery voltage at predetermined time intervals during cranking. The voltage monitoring module calculates an average of the plurality of voltage delta values.

In other features, the voltage monitoring module compares the average and a predetermined average threshold and selectively disables the auto stop/start module when the average is less than the predetermined average threshold. The voltage monitoring module enables the auto stop/start module if a voltage of the ultra-capacitor is greater than a predetermined threshold.

In other features, the voltage monitoring module compares the voltage of the ultra-capacitor to a predetermined voltage threshold and charges the ultra-capacitor if the voltage of the ultra-capacitor is less than the predetermined voltage threshold.

In other features, the system includes an engine control module including the voltage monitoring module and the auto start/stop module. The ultra-capacitor and battery system further includes an ultra-capacitor controller and further comprising a bus arranged between the engine control module and the ultra-capacitor controller.

In other features, the voltage monitoring module determines that the cranking is occurring when the auto start event is in progress and a speed of the engine is greater than a first predetermined engine speed and less than a second predetermined engine speed.

Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a functional block diagram of an example of an engine control system including an auto stop/start system and a battery and ultra-capacitor system according to the present disclosure;

FIG. 2 is a functional block diagram of an example of the battery and ultra-capacitor system of FIG. 1;

FIG. 3 is a flowchart illustrating an example of a method for monitoring a voltage performance of the battery according to the present disclosure; and

FIG. 4 is a flowchart illustrating an example of a method for monitoring charging an ultra-capacitor according to the present disclosure.

DETAILED DESCRIPTION

An engine control module and starter selectively start and stop an engine of a vehicle in response to vehicle startup and shutdown commands from the operator (e.g., transitioning an ignition key or start button to “ON” or to “OFF”). The control module may also automatically initiate auto stop events and auto start events between the vehicle startup command and the vehicle shutdown command while the ignition key is “ON”.

The control module may selectively initiate an auto stop event and shut down the engine, for example, when the vehicle is stopped while the driver applies pressure to a brake pedal and/or other enabling conditions are present. The control module may selectively initiate an auto start event and re-start the engine when the driver removes pressure from the brake pedal and/or other enabling conditions are present.

Systems and methods according to the present disclosure include an ultra-capacitor to assist the battery during auto start events. The systems and methods monitor the performance of the battery and ultra-capacitor. If the battery or ultra-capacitor do not meet performance criteria, one or more fault codes may be set and auto stop/start events may be disabled for a given trip to maintain the stability of battery voltage. As used herein, the term ‘trip’ refers to the period between an ignition ON event and an ignition OFF event.

During operation, the ultra-capacitor is charged to store energy. After the charge operation is complete, auto stop events are allowed. When an auto start event occurs, the ultra-capacitor releases the stored energy to reduce battery voltage dips. Reducing the battery voltage dips allows the auto stop/start system to operate in additional situations. For example, use of the ultra-capacitor allows the auto stop/start system to work at lower temperatures. As a result of the increased use of the auto stop/start system, fuel economy is improved.

Referring now to FIG. 1, a functional block diagram of an example engine system 100 is presented. The engine system 100 includes an engine 102 that combusts an air/fuel mixture to produce drive torque for a vehicle. Air is drawn into an intake manifold 104 through a throttle valve 106. The throttle valve 106 regulates air flow into the intake manifold 104. Air within the intake manifold 104 is drawn into one or more cylinders of the engine 102, such as cylinder 108.

One or more fuel injectors, such as fuel injector 110, inject fuel that mixes with air to form an air/fuel mixture. In various implementations, one fuel injector may be provided for each cylinder of the engine 102. The fuel injectors may be associated with an electronic or mechanical fuel injection system, a jet or port of a carburetor, or another fuel injection system. The fuel injectors may be controlled to provide a desired air/fuel mixture for combustion, such as a stoichiometric air/fuel mixture.

An intake valve 112 opens to allow air into the cylinder 108. A piston (not shown) compresses the air/fuel mixture within the cylinder 108. In some engine systems, a spark plug 114 initiates combustion of the air/fuel mixture within the cylinder 108. In other types of engine systems, such as diesel engine systems, combustion may be initiated without the spark plug 114.

Combustion of the air/fuel mixture applies force to the piston, which rotatably drives a crankshaft (not shown). The engine 102 outputs torque via the crankshaft. A flywheel 120 is coupled to the crankshaft and rotates with the crankshaft. Torque output by the engine 102 is selectively transferred to a transmission 122 via a torque transfer device 124. More specifically, the torque transfer device 124 selectively couples the transmission 122 to the engine 102 and de-couples the transmission 122 from the engine 102. The torque transfer device 124 may include, for example, a torque converter and/or one or more clutches. The transmission 122 may include, for example, a manual transmission, an automatic transmission, a semi-automatic transmission, an auto-manual transmission, or another suitable type of transmission.

Exhaust produced by combustion of the air/fuel mixture is expelled from the cylinder 108 via an exhaust valve 126. The exhaust is expelled from the cylinders to an exhaust system 128. The exhaust system 128 may treat the exhaust before the exhaust is expelled from the exhaust system 128. Although one intake and exhaust valve are shown and described as being associated with the cylinder 108, more than one intake and/or exhaust valve may be associated with each cylinder of the engine 102.

An engine control module (ECM) 130 controls the torque output of the engine 102. For example only, the ECM 130 may control the torque output of the engine 102 via various engine actuators. The engine actuators may include, for example, a throttle actuator module 132, a fuel actuator module 134, and a spark actuator module 136. The engine system 100 may also include other engine actuators, and the ECM 130 may control the other engine actuators.

Each engine actuator controls an operating parameter based on a signal from the ECM 130. For example only, the throttle actuator module 132 may control opening of the throttle valve 106, the fuel actuator module 134 may control amount and timing of fuel injection, and the spark actuator module 136 may control spark timing.

The ECM 130 may control the torque output of the engine 102 based on, for example, driver inputs and various other inputs. The other inputs may include, for example, inputs from a transmission system, inputs from a hybrid control system, inputs from a stability control system, inputs from a chassis control system, and other suitable vehicle systems.

The driver inputs may include, for example, an accelerator pedal position (APP), a brake pedal position (BPP), and vehicle operation commands. An APP sensor 142 measures position of an accelerator pedal (not shown) and generates the APP based on the position. A BPP sensor 144 monitors actuation of a brake pedal (not shown) and generates the BPP accordingly. The vehicle operation commands may be made via actuation of, for example, an ignition key, one or more ignition buttons/switches, and/or one or more suitable vehicle ignition system inputs 148. In vehicles having a manual transmission, the driver inputs provided to the ECM 130 may also include a clutch pedal position (CPP). A CPP sensor 150 monitors actuation of a clutch pedal (not shown) and generates the CPP accordingly.

In some implementations, the APP sensor 142, the BPP sensor 144, and the CPP sensor 150 may measure the position of the associated pedal and generate the APP, the BPP, and the CPP signals, respectively, based on the measured position of the associated pedal. In other implementations, the APP sensor 142, the BPP sensor 144, and the CPP sensor 150 may each include one or more switches and may generate the APP, the BPP, and the CPP, respectively, indicating whether the associated pedal is being actuated away from a predetermined resting position. While the APP sensor 142, the BPP sensor 144, and the CPP sensor 150 are shown and described, one or more additional APP, BPP, and/or CPP sensors may be provided.

The driver inputs may also include one or more cruise control inputs. A cruise control module 154 may provide cruise control inputs to the ECM 130 based on user inputs and vehicle surroundings inputs. The user inputs may include, for example, a speed set input, a cruise control on/off input, a resume speed input, and/or one or more suitable user inputs.

The ECM 130 may selectively make control decisions for the engine system 100 based on one or more parameters. A vehicle speed sensor 152 measures speed of the vehicle and generates a vehicle speed signal. For example only, the vehicle speed sensor 152 may generate the vehicle speed based on a transmission output shaft speed (TOSS), one or more wheel speeds, and/or another suitable measure of the vehicle speed. The ECM 130 may also receive operating parameters measured by other sensors 155, such as oxygen in the exhaust, engine speed, engine coolant temperature, intake air temperature, mass air flowrate, oil temperature, manifold absolute pressure, and/or other suitable parameters.

The ECM 130 selectively shuts down the engine 102 when a vehicle shutdown command is received. For example only, the ECM 130 may disable the injection of fuel, disable the provision of spark, and perform other engine shutdown operations to shut down the engine 102 when a vehicle shutdown command is received.

While the engine 102 is cranked pursuant to the receipt of a vehicle startup command (e.g., the ignition key is transitioned ON), a starter motor 160 is selectively engaged with the engine 102 to crank the engine and to initiate a startup event. For example only, the starter motor 160 may be engaged with the engine 102 when a vehicle startup command is received. The starter motor 160 may engage the flywheel 120 or other suitable component(s) that may drive rotation of the crankshaft.

A starter motor actuator 162, such as a solenoid, selectively engages the starter motor 160 with the engine 102. A starter actuator module 164 controls the starter motor actuator 162, and therefore the starter motor 160, based on signals from the ECM 130. For example only, the ECM 130 may command engagement of the starter motor 160 when the vehicle startup command is received.

The starter actuator module 164 selectively applies current to the starter motor 160 when the starter motor 160 is engaged with the engine 102. For example only, the starter actuator module 164 may include a starter relay. The application of current to the starter motor 160 drives rotation of the starter motor 160, and the engaged portion of the starter motor 160 drives rotation of the crankshaft. Driving rotation of the crankshaft to start the engine 102 may be referred to as engine cranking.

Once the engine 102 is deemed running after the engine startup event, the starter motor 160 may be disengaged from the engine 102, and the flow of current to the starter motor 160 may be discontinued. The engine 102 may be deemed running, for example, when the engine speed exceeds a predetermined speed, such as a predetermined idle speed. For example only, the predetermined idle speed may be approximately 700 rpm. Engine cranking may be said to be completed when the engine 102 is deemed running. Current provided to the starter motor 160 may be provided by, for example, a battery and ultra-capacitor system 190.

Other than commanded vehicle startups and vehicle shutdowns, the ECM 130 may include an auto stop/start module 180 that selectively initiates auto stop events and auto start events of the engine 102. An auto stop event includes shutting down the engine 102 when one or more predetermined auto stop criteria are satisfied when vehicle shutdown has not been commanded (e.g., while the ignition key remains ON). The engine 102 may be shut down and the provision of fuel to the engine 102 may be disabled, for example, to increase fuel economy (by decreasing fuel consumption).

While the engine 102 is shut down during an auto stop event, the auto stop/start module 180 may selectively initiate an auto-start event. An auto-start event may include, for example, supplying fuel to the engine 102, supplying spark, engaging the starter motor 160 with the engine 102, and applying current to the starter motor 160 to start the engine 102.

The auto stop/start module 180 may selectively initiate auto stop events and auto start events, for example, based on the APP, the BPP, the vehicle speed, the CPP, the voltage state of the battery, the charge state of the ultra-capacitor and/or one or more other suitable parameters. For example only, the auto stop/start module 180 may initiate an auto-stop event when the brake pedal is depressed and the vehicle speed is less than a predetermined speed. While the engine 102 is shut down for the auto stop event, the auto stop/start module 180 may selectively initiate an auto start event when the brake pedal is released.

The ECM 130 may further include a voltage monitoring module 182 that monitors voltages of the battery and the ultra-capacitor. Operation of the voltage monitoring module 182 will be described further below in conjunction with FIGS. 3-4.

Referring now to FIG. 2, the battery and ultra-capacitor system 190 includes a battery 200, an ultra-capacitor controller 204, a DC-DC converter 208, switches 210 and 212, an ultra-capacitor 214, and temperature sensors 218, 220 and 222. The engine control module 130 may be connected to the ultra-capacitor controller 204 by a bus 206. In some examples, the bus 206 includes a local interconnect network (LIN) bus, although other types of buses may be used.

The DC-DC converter 208 includes a first terminal connected to a first terminal of the battery 201 and a second terminal connected between the switch and the ultra-capacitor 214. The switch 210 is connected between a second terminal of the battery 200 and a first terminal of the ultra-capacitor 214. The switch 212 is connected between the negative terminal of the battery 200 and chassis ground. The second terminal of the ultra-capacitor 214 is connected to chassis ground. The ultra-capacitor controller 204 is connected to the DC-DC converter 208, the temperature sensors 218, 220 and 222, and the switches 210 and 212. In addition, the ultra-capacitor controller 204 communicates with the engine control module 206.

During operation, the switch 212 is typically closed to connect the battery 200 to chassis ground and the switch 210 is open. During auto start events, the switch 210 is selectively closed and switch 212 is opened to provide assistance from the ultra-capacitor 214 to the battery 200 to prevent voltage dips. During charging, the DC-DC converter 208 supplies power from the battery 200 to the ultra-capacitor 214 to charge the ultra-capacitor 214. The temperature sensors 218, 220 and 222 monitor temperatures of the DC-DC converter 208, the switch 212 and the ultra-capacitor 214, respectively.

Referring now to FIG. 3, a method for monitoring voltage performance of the battery and ultra-capacitor is shown. At 310, the method determines whether the ultra-capacitor is operating at a temperature greater than a predetermined temperature or whether the ignition key is in an accessory (ACC) or off position. If 310 is true, control continues at 312 and resets the voltage diagnostic.

If 310 is false, control continues with 314 and determines whether the engine is running. If 314 is false, control continues with 312. Otherwise, control continues with 318 and determines whether the voltage on the ultra-capacitor (V_(UC)) is greater than a predetermined arm voltage threshold V_(arm) _(_) _(threshold). If 318 is false, control disables auto stop/start functionality at 322, charges the ultra-capacitor at 326 to a predetermined target voltage V_(UC) _(_) _(target) and continues with 318. If 318 is true, control continues with 330 and allows auto stops and enables assisted auto starts using the ultra-capacitor.

At 334, control determines whether the engine is running. If 334 is false, control continues with 338 and determines whether an auto stop event has occurred. If 338 is true, control monitors and filters system voltage (or battery voltage) during an auto stop. At 346, control determines whether there is an engine ON request. If 346 is false, control returns to 342. When 346 is true, control captures filtered system voltage prior to a crank event (FiltRunCrnkFinal). Control continues with 354 and determines whether an auto start is in progress, engine RPM is greater than a predetermined minimum crank RPM, and a time duration of the auto start is greater than a delay timer. If 354 is false, control returns to 354. When 354 is true, control discharges the ultra-capacitor to compensate for a voltage dip in the battery voltage at 356.

At 360, control accumulates samples of voltage delta, which is the difference between the cumulative FiltRunCrnkFinal and the system voltage (SysVolt). Alternatively, the voltage delta may be equal to an accumulated absolute voltage delta (SysVolt−0) during the auto start assist.

Control continues with 364 and determines whether the engine is running or the number of voltage samples is greater than a predetermined number of samples. If 364 is false, control returns to 360. When 364 is true, control continues with 368 and increments a StartsThisTrip counter. At 372, control determines whether the StartsThisTrip counter is greater than a predetermined counter value. In some examples, the counter may include starts over multiple trips before reporting. If 372 is false, control continues with 310. If 372 is true, control calculates an average voltage delta during auto start at 376.

At 380, control determines whether the average voltage delta is greater than a predetermined average voltage delta threshold V_(TH) _(_) _(avg). If 380 is true, control reports a voltage diagnostic failure at 384 and disables auto stop/start for the trip at 386. At 388, control resets the diagnostic and returns to 310. If 380 is false, control continues with 390 and reports a voltage diagnostic pass and does not disable auto stop/starts for the trip.

Referring now to FIG. 4, another diagnostic for evaluating charging of the ultra-capacitor is shown. Control begins with 410 where multiple conditions are evaluated including whether a temperature of the ultra-capacitor is above a predetermined temperature OR a derating level of the ultra-capacitor has changed OR the arm voltage threshold has changed significantly since a prior loop.

If 410 is true, the charging diagnostic is reset at 412 and control returns to 410. If 410 is false, control continues with 414 and determines whether the engine is running and the system voltage is greater than a predetermined minimum voltage. If 414 is false, control continues with 416 and pauses the diagnostic for a predetermined period. If 414 is true, control charges the ultra-capacitor if V_(UC)<V_(target). At 420, control determines whether the initial diagnostic delay has expired (which allows the ultra-capacitor time to charge from a discharged state). If 420 is false, control continues with 416. If 420 is true, control continues at 424 and determines a charge threshold V_(UC) _(_) _(TH1) based on the derating level of the ultra-capacitor. Under normal conditions, the charge threshold is the same as the threshold to arm and auto start.

At 430, control measures the ultra-capacitor voltage and increments a timer. Alternatively, the number of sample counts may be incremented if using a fail/sample count (X/Y) strategy where and a failure counter is incremented if V_(UC)<V_(UC) _(_) _(TH1). At 432, control determines whether a timer has expired (or sample counts is greater than or equal to a sample count limit when using the X/Y strategy). If 432 is false, control returns to start and rechecks enable conditions but does not reset counters.

If 432 is true, control continues with 434. At 434, control determines whether V_(UC)<V_(UC) _(_) _(TH1) (or if the X/Y strategy is used, fail counts>fail threshold). If 434 is true, control continues with 438 and reports a charging diagnostic failure. In some examples, auto stop/starts are disabled for the trip or for a predetermined period. If 434 is false, the charging diagnostic is passed at 444. Control continues from 438 and 444 with 440 where the diagnostic is reset and returns to start.

The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

In this application, including the definitions below, the term “module” or the term “controller” may be replaced with the term “circuit.” The term “module” may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.

The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing. In a further example, a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.

The term code, as used above, may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.

The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.

The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.

The computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language) or XML (extensible markup language), (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective C, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5, Ada, ASP (active server pages), PHP, Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, and Python®.

None of the elements recited in the claims are intended to be a means-plus-function element within the meaning of 35 U.S.C. § 112(f) unless an element is expressly recited using the phrase “means for,” or in the case of a method claim using the phrases “operation for” or “step for.” 

What is claimed is:
 1. A system comprising: an ultra-capacitor and battery system comprising a battery, a DC-DC converter, and an ultra-capacitor; an auto stop/start module configured to perform an auto stop event of an engine of a vehicle and an auto start event of the engine of the vehicle based on operating parameters while an ignition is ON; and a voltage monitoring module configured to, in response to a request for the auto start event, selectively discharge the ultra-capacitor during cranking to compensate for a voltage dip in a battery voltage of the battery for the auto start event, calculate a plurality of voltage delta values by generating a difference between the battery voltage prior to the cranking and the battery voltage at predetermined time intervals during the cranking, wherein the plurality of voltage delta values are accumulated while the ultra-capacitor discharges during the cranking, calculate a voltage value based on the plurality of voltage delta values, and selectively disable the auto stop/start module when the voltage value is less than a predetermined threshold, wherein the voltage value comprises an average of the plurality of voltage delta values.
 2. The system of claim 1, wherein the voltage monitoring module compares the average and the predetermined threshold and selectively disables the auto stop/start module when the average is less than the predetermined threshold, wherein the predetermined threshold is a predetermined average threshold.
 3. The system of claim 1, wherein the voltage monitoring module enables the auto stop/start module if a voltage of the ultra-capacitor is greater than a predetermined voltage threshold.
 4. The system of claim 3, wherein the voltage monitoring module compares the voltage of the ultra-capacitor to the predetermined voltage threshold and charges the ultra-capacitor if the voltage of the ultra-capacitor is less than the predetermined voltage threshold.
 5. The system of claim 1, further comprising an engine control module including the voltage monitoring module and the auto start/stop modulo auto stop/start module.
 6. The system of claim 5, further comprising a bus, wherein the ultra-capacitor and battery system further includes an ultra-capacitor controller operatively connected to a first switch disposed between the ultra-capacitor and the battery and a second switch disposed between the battery and ground, wherein the bus is arranged between the engine control module and the ultra-capacitor controller, wherein the ultra-capacitor controller is configured to selectively close the first switch and selectively opens the second switch allowing the ultra-capacitor to compensate for the voltage dip in the battery voltage of the battery during the auto start event.
 7. The system of claim 1, wherein the voltage monitoring module is configured to determine that the cranking is occurring when the auto start event is in progress and a speed of the engine is greater than a first predetermined engine speed and less than a second predetermined engine speed.
 8. A method comprising: providing an ultra-capacitor and battery system comprising a battery, a DC-DC converter, and an ultra-capacitor; performing an auto stop event of an engine of a vehicle and an auto start event of the engine of the vehicle based on operating parameters while an ignition is ON; and in response to a request for the auto start event: discharging the ultra-capacitor during cranking to compensate for a voltage dip in a battery voltage of the battery for the auto start event, accumulating a plurality of voltage delta values while the ultra-capacitor discharges during the cranking, wherein the plurality of voltage delta values are calculated by generating a difference between the battery voltage prior to the cranking and the battery voltage at predetermined time intervals during the cranking, calculating an average of the plurality of voltage delta values, and disabling auto stop/starts when the average is less than a predetermined threshold.
 9. The method of claim 8, further comprising: comparing the average and the predetermined threshold; and selectively disabling the auto stop/starts when the average is less than the predetermined threshold, wherein the predetermined threshold is a predetermined threshold.
 10. The method of claim 8, further comprising enabling the auto stop/starts if a voltage of the ultra-capacitor is greater than a predetermined voltage threshold.
 11. The method of claim 10, further comprising: comparing the voltage of the ultra-capacitor to the predetermined voltage threshold; and charging the ultra-capacitor if the voltage of the ultra-capacitor is less than the predetermined voltage threshold.
 12. The method of claim 8, further comprising determining that the cranking is occurring when the auto start event is in progress and a speed of the engine is greater than a first predetermined engine speed and less than a second predetermined engine speed.
 13. A system comprising: an ultra-capacitor and battery system comprising a battery, a DC-DC converter, an ultra-capacitor, and an ultra-capacitor controller operatively connected to a first switch disposed between the ultra-capacitor and the battery and a second switch disposed between the battery and ground; an auto stop/start module configured to perform an auto stop event of an engine of a vehicle and an auto start event of the engine of the vehicle based on operating parameters while an ignition is ON; and a voltage monitoring module configured to, in response to a request for the auto start event, selectively discharge the ultra-capacitor during cranking for the auto start event to compensate for a voltage dip in a battery voltage of the battery, calculate a plurality of voltage delta values by generating a difference between the battery voltage prior to the cranking and the battery voltage at predetermined time intervals during the cranking, wherein the plurality of voltage delta values are accumulated while the ultra-capacitor discharges during the cranking, calculate an average of the plurality of voltage delta values, compare the average and a predetermined threshold, and selectively disable the auto stop/start module when the average is less than the predetermined threshold, wherein the ultra-capacitor controller is configured to selectively close the first switch and selectively opens the second switch allowing the ultra-capacitor to compensate for the voltage dip in the battery voltage of the battery during the auto start event. 